Electrical components such as semiconductors typically generate heat during operation. To prevent excess heat from damaging electrical components, heat dissipating devices such as heat spreaders, heat sinks and heat pipes have been developed. A typical heat spreader, heat sink or heat pipe is made of heat-conducting material and is placed in thermal communication with a heat-generating component so that it draws heat away from the heat-generating component.
Because surfaces of a heat dissipating device and an electrical component are not completely smooth, at least on a microscopic level, it is typically impossible to achieve a perfect contact between a surface of a heat dissipating device and a surface of a electrical component. Since air is a poor thermal conductor, air pockets that may remain between the surfaces can inhibit the conduction of heat from the electrical component to the heat dissipating device. To solve this problem, and to conduct heat from a device that generates heat, such as a die, to a device that dissipates heat, such as a heat spreader, heat sink or heat pipe, thermal interface materials have been developed to fill the gaps between the device that generates heat and the device that dissipates heat. Typically, thermal interface materials are selected to have high thermal conductivity, so that they efficiently facilitate the transfer of heat from the heat-generating device to the heat dissipating device.
A typical electronic assembly or integrated semiconductor package assembly may include a semiconductor die, which generates heat when operated, an integrated heat spreader, heat sink or heat pipe and a thermal interface material interposed between the semiconductor die and the heat spreader, heat sink or heat pipe.
A disadvantageous process for the fabrication of an integrated semiconductor package assembly requires that multiple process steps be carried out at the final stage of assembly. Typically, these steps include dispensing a thermal interface material onto the semiconductor die in liquid or gel form or as a solid, pre-cut preform, placing the heat spreader onto the die so that the heat spreader contacts the thermal interface material, applying spring clips to secure the heat spreader to the die, and then curing the thermal interface material. This process is disadvantageous, particularly if the die and the heat spreader are assembled at a remote time and place from when they are first manufactured, because the thermal interface material must be stored and transported to the remote time and place so that it is on hand at the point of final assembly. For example, it is a common practice for a manufacturer to ship a heat spreader and semiconductor die to a customer in unassembled form, with the customer having the task of joining the two in a semiconductor assembly. Under the disadvantageous process, it is necessary for the customer to obtain the thermal interface material or have it on hand so that it can be applied between the heat spreader and the semiconductor die, as described above. Further, the multiple process steps add to the cost of the integrated semiconductor package assembly.